Re: [RFC PATCH] ext4: convert swap_inode_data() over to use swap() on most of the fields

From: Jan Kara
Date: Wed Jan 04 2017 - 10:43:39 EST


On Tue 20-12-16 10:55:41, Jeff Layton wrote:
> For some odd reason, it forces a byte-by-byte copy of each field. A
> plain old swap() on most of these fields would be more efficient. We
> do need to retain one memswap however as that field is an array.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> fs/ext4/ioctl.c | 18 ++++++++----------
> 1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index 49fd1371bfa2..fb844da4836f 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -60,18 +60,16 @@ static void swap_inode_data(struct inode *inode1, struct inode *inode2)
> ei1 = EXT4_I(inode1);
> ei2 = EXT4_I(inode2);
>
> - memswap(&inode1->i_flags, &inode2->i_flags, sizeof(inode1->i_flags));
> - memswap(&inode1->i_version, &inode2->i_version,
> - sizeof(inode1->i_version));
> - memswap(&inode1->i_blocks, &inode2->i_blocks,
> - sizeof(inode1->i_blocks));
> - memswap(&inode1->i_bytes, &inode2->i_bytes, sizeof(inode1->i_bytes));
> - memswap(&inode1->i_atime, &inode2->i_atime, sizeof(inode1->i_atime));
> - memswap(&inode1->i_mtime, &inode2->i_mtime, sizeof(inode1->i_mtime));
> + swap(inode1->i_flags, inode2->i_flags);
> + swap(inode1->i_version, inode2->i_version);
> + swap(inode1->i_blocks, inode2->i_blocks);
> + swap(inode1->i_bytes, inode2->i_bytes);
> + swap(inode1->i_atime, inode2->i_atime);
> + swap(inode1->i_mtime, inode2->i_mtime);
>
> memswap(ei1->i_data, ei2->i_data, sizeof(ei1->i_data));
> - memswap(&ei1->i_flags, &ei2->i_flags, sizeof(ei1->i_flags));
> - memswap(&ei1->i_disksize, &ei2->i_disksize, sizeof(ei1->i_disksize));
> + swap(ei1->i_flags, ei2->i_flags);
> + swap(ei1->i_disksize, ei2->i_disksize);
> ext4_es_remove_extent(inode1, 0, EXT_MAX_BLOCKS);
> ext4_es_remove_extent(inode2, 0, EXT_MAX_BLOCKS);
>
> --
> 2.7.4
>
> --
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--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR